CFD Simulation of Air–Water Interactions in Rapidly Filling Horizontal Pipe with Entrapped Air

2021 ◽  
Author(s):  
Biao Huang ◽  
Mengge Fan ◽  
Jiachun Liu ◽  
David Z. Zhu
Keyword(s):  
Cfd Simulation ◽  
Horizontal Pipe ◽  
Entrapped Air

Experimental Visualization and Numerical Simulation of Liquid-Gas Two-Phase Flows in a Horizontal Pipe

2017 ◽  
Author(s):  
Milad Darzi ◽  
Chanwoo Park
Keyword(s):  
Numerical Simulation ◽  
Gas Flow ◽  
Cfd Simulation ◽  
Glass Tube ◽  
Flow Patterns ◽  
Two Phase Flows ◽  
Two Phase ◽  
Mixture Flow ◽  
Horizontal Pipe ◽  
Flow Rates

This paper presents the results of both visualization experiment and numerical simulation for two-phase (water-air mixture) flows in a horizontal tube. A visualization experimental setup was used to observe various two-phase flow patterns for different flow rates of water/air mixture flow in a glass tube of 12 mm in diameter. Total of 303 experimental data points were compared with Mandhane’s flow map. Most of the data for stratified, plug and slug flows were found to be in good agreement. However, annular flow was observed for relatively lower gas flow rates and also wavy flow occurred at relatively higher liquid flow rates in this experiment. A three-dimensional Computational Fluid Dynamics (CFD) simulation was performed using OpenFOAM employing “interFoam” as the solver to simulate the two-phase flows in horizontal pipe based on Volume-Of-Fluid (VOF) method. The simulated and experimentally observed flow patterns for the same set of superficial velocities shows acceptable similarities for stratified, wavy, plug, slug and annular flows. Also, the computed values of the void fraction and pressure drop for the numerical simulations shows reasonable agreement with well-known correlations in literature.

scholarly journals Expulsion of Entrapped Air in a Rapidly Filling Horizontal Pipe

2020 ◽  
Vol 146 (7) ◽  
pp. 04020047
Author(s):  
Ling Zhou ◽  
Yun Cao ◽  
Bryan Karney ◽  
Anton Bergant ◽  
Arris S. Tijsseling ◽  
...  
Keyword(s):  
Horizontal Pipe ◽  
Entrapped Air

Transient Analysis of Mixed Free-Surface-Pressurized Flows With Modified Slot Model: Part 1 — Computational Model and Experiment

2003 ◽  
Author(s):  
Kazutoshi Arai ◽  
Katsuhiro Yamamoto
Keyword(s):  
Free Surface ◽  
Computational Model ◽  
Drainage System ◽  
Scale Model ◽  
Small Scale ◽  
Horizontal Pipe ◽  
Pressurized Flows ◽  
Calculation Results ◽  
Gas Liquid Flow ◽  
Entrapped Air

A new computational model is developed here to analyze the influence of entrapped air on free-surface-pressurized flows in a drainage system. A virtual slot with ceiling on the top of the pipe is introduced to treat a separated gas-liquid flow. This model is a modified model of Preissmann’s and is applicable not only to open channel flow and closed conduit flow but also pressurized flow with entrapped air. Compared to experimental results using the model of 1/50 scale of actual drainage system, the calculation results show that the entrapped air in a horizontal pipe advances the time of pressure rising and makes the maximum value of pressure higher. The escape flow of entrapped air at a dropshaft is caused by long waves pushing the air in the horizontal pipe, and then the pipe slope affects the flow rate of air. The air compressibility has less effect on the transient separated air-water flow in the small-scale model.

scholarly journals MODELLING AIR AND WATER TWO-PHASE ANNULAR FLOW IN A SMALL HORIZONTAL PIPE

2016 ◽  
Vol 42 ◽  
pp. 1660158 ◽  
Author(s):  
JUN YAO ◽  
YUFENG YAO ◽  
ANTONINO ARINI ◽  
STUART MCIIWAIN ◽  
TIMOTHY GORDON
Keyword(s):  
Experimental Data ◽  
Film Thickness ◽  
Liquid Film ◽  
Annular Flow ◽  
Cfd Simulation ◽  
Two Phase Flow ◽  
Liquid Film Thickness ◽  
Phase Flow ◽  
Two Phase ◽  
Horizontal Pipe

Numerical simulation using computational fluid dynamics (CFD) has been carried out to study air and water two-phase flow in a small horizontal pipe of an inner diameter of 8.8mm, in order to investigate unsteady flow pattern transition behaviours and underlying physical mechanisms. The surface liquid film thickness distributions, determined by either wavy or full annular flow regime, are shown in reasonable good agreement with available experimental data. It was demonstrated that CFD simulation was able to predict wavy flow structures accurately using two-phase flow sub-models embedded in ANSYS-Fluent solver of Eulerian–Eulerian framework, together with a user defined function subroutine ANWAVER-UDF. The flow transient behaviours from bubbly to annular flow patterns and the liquid film distributions revealed the presence of gas/liquid interferences between air and water film interface. An increase of upper wall liquid film thickness along the pipe was observed for both wavy annular and full annular scenarios. It was found that the liquid wavy front can be further broken down to form the water moisture with liquid droplets penetrating upwards. There are discrepancies between CFD predictions and experimental data on the liquid film thickness determined at the bottom and the upper wall surfaces, and the obtained modelling information can be used to assist further 3D user defined function subroutine development, especially when CFD simulation becomes much more expense to model full 3D two-phase flow transient performance from a wavy annular to a fully developed annular type.

Sign in / Sign up

Export Citation Format

Share Document